Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F112/00—Homopolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring
  • C08F112/02—Monomers containing only one unsaturated aliphatic radical
  • C08F112/04—Monomers containing only one unsaturated aliphatic radical containing one ring
  • C08F112/06—Hydrocarbons
  • C08F112/08—Styrene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
  • C08G63/02—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds
  • C08G63/12—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds derived from polycarboxylic acids and polyhydroxy compounds
  • C08G63/16—Dicarboxylic acids and dihydroxy compounds
  • C08G63/18—Dicarboxylic acids and dihydroxy compounds the acids or hydroxy compounds containing carbocyclic rings
  • C08G63/181—Acids containing aromatic rings
  • C08G63/183—Terephthalic acids
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J3/00—Processes of treating or compounding macromolecular substances
  • C08J3/005—Processes for mixing polymers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
  • C08J5/18—Manufacture of films or sheets
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L25/00—Compositions of, homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring; Compositions of derivatives of such polymers
  • C08L25/02—Homopolymers or copolymers of hydrocarbons
  • C08L25/04—Homopolymers or copolymers of styrene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
  • C08L67/02—Polyesters derived from dicarboxylic acids and dihydroxy compounds
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
  • D01F6/88—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from mixtures of polycondensation products as major constituent with other polymers or low-molecular-weight compounds
  • D01F6/92—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from mixtures of polycondensation products as major constituent with other polymers or low-molecular-weight compounds of polyesters
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2500/00—Characteristics or properties of obtained polyolefins; Use thereof
  • C08F2500/17—Viscosity
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2367/00—Characterised by the use of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Derivatives of such polymers
  • C08J2367/02—Polyesters derived from dicarboxylic acids and dihydroxy compounds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L25/00—Compositions of, homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring; Compositions of derivatives of such polymers
  • C08L25/02—Homopolymers or copolymers of hydrocarbons
  • C08L25/04—Homopolymers or copolymers of styrene
  • C08L25/06—Polystyrene

Definitions

• the present invention is directed to a polymer blend comprising poly(trimethylene arylate), especially poly(trimethylene terephthalate), and polystyrene, that is useful in the production of shaped articles such as fibers, films, and molded structures.
• the invention is also directed to the use of the masterbatch in the production of fibers, films and molded structures.
• Poly(thmethylene terephthalate), also known as poly(propylene terephthalate), or, less formally, as “3GT” polymer, is well known in the art. The properties and manufacturing thereof are described by Chuah in The Encyclopedia of Polymer Science, on-line, DOI
• PS polystyrene
• compositions were prepared by co-feeding pellets of the two polymers into a twin screw extruder or by making a salt and pepper blend of pellets of the two polymers in the desired proportions and then feeding the resulting pellet mixture into a twin screw extruder.
• the extrudate was extruded as a strand and chopped into pellets. These blend pellets were then fed to a spinning machine to melt spin fiber.
• U.S. Pat. No. 4,475,330 discloses a polyester multifilament yarn made from polyester filaments consisting essentially of (a) a copolymer of two or more monomers selected from the group consisting of ethylene terephthalate, trimethylene terephthalate and tetramethylene
• terephthalate and/or (b) a blend of two or more polymers of ethylene terephthalate, trimethylene terephthalate and tetramethylene terephthalate.
• This patent describes blends of polyesters with 3 to 15% of non-crystalline polymer, preferably styrene polymers or methacrylate polymers.
• the masterbatch, or concentrate, technology of the present invention represents a significant cost savings over the present practice of fiber spinning. Additionally, the composition hereof has utility in the preparation of fibers, toughened molded parts and films of
• the present invention provides a composition
• a composition comprising a poly (trimethylene arylate) and polystyrene dispersed therewithin, the polystyrene at a concentration 15% to 40% by weight on the basis of total polymer weight.
• the present invention provides a process comprising combining poly (trimethylene arylate) and 15 % to 40% by weight on the basis of total polymer weight, of polystyrene, melting the poly (trimethylene arylate) and polystyrene, and melt blending the thus melted poly (trimethylene arylate) and polystyrene in a high shear melt mixer to provide a melt composition comprising a poly (trimethylene arylate) and a polystyrene dispersed therewithin.
• Figure 1 is a schematic representation of one embodiment of melt feeding a spinneret.
• Figure 2 is a schematic representation of one embodiment of the fiber spinning process.
• Poly(thmethylene arylate) polymers suitable for the practice of the invention include but are not limited to poly(trimethylene terephthalate), poly(trimethylene isophthalate), poly(trimethylene naphthalate), and mixtures and copolymers thereof.
• poly(trimethylene arylate) is a poly(trimethylene terephthalate) (PTT).
• the invention provides a composition comprising a poly (trimethylene arylate) and polystyrene wherein the polystyrene is dispersed therewithin the composition and wherein the polystyrene is found at a concentration of 15% to 40% by weight, on the basis of total polymer weight.
• PS polystyrene
• PTT polystyrene
• poly(trimethylene terephthalate) and will be employed in lieu of the more generic poly(trimethylene arylate).
• technology described herein can readily be adapted to other poly(thmethylene arylate) polymers, and the invention is considered to encompass poly(thmethylene arylate) polymers.
• PTT is meant to encompass homopolymers and copolymers containing at least 70 mole % thmethylene terephthalate repeat units.
• the polymer compositions are described in terms of weight per cent of ingredients based upon the total weight of polymers.
• the percentage of PS in the composition is expressed as a percentage of the total weight of the polymers, including, e.g., PTT, and any other additional polymers that may be incorporated into the
• copolymer shall be understood to encompass terpolymers, tetrapolymers and so forth, as well as dipolymers.
• the present invention provides a composition comprising PTT and 15% to 40 % by weight of PS dispersed therewith in.
• the PTT is a continuous phase or "matrix" and the PS is a discontinuous phase dispersed within the PTT matrix.
• the composition contemplated according to the invention includes a molten composition and a solid composition, and any transition states there-between.
• the PTT is molten and the PS is dispersed within the PTT matrix as molten droplets.
• the PTT is solid and the PS is dispersed within the PTT matrix as solid particles.
• the composition comprises 50 to 85 weight % of the PTT, and 15 to 40 weight % of PS, by weight of the total polymer in the composition, and may comprise up to 30 weight % of other polyesters.
• Other polyesters include but are not limited to poly (ethylene
• the composition comprises 50 to 80 % of the PTT, and 20 to 30 % of PS, and up to 30 % of other
• Suitable PTT polymer is formed by the condensation polymerization of 1 ,3-propanediol and terephthalic acid or dimethylterephthalate.
• One or more suitable comonomers for copolymehzation therewith is selected from the group consisting of linear, cyclic, and branched aliphatic dicarboxylic acids or esters having 4-12 carbon atoms (for example butanedioic acid, pentanedioic acid, hexanedioic acid, dodecanedioic acid, and 1 ,4-cyclohexanedicarboxylic acid, and their corresponding esters); aromatic dicarboxylic acids or esters other than terephthalic acid or ester and having 8-12 carbon atoms (for example isophthalic acid and 2,6- naphthalenedicarboxylic acid); linear, cyclic, and branched aliphatic diols having 2-8 carbon atoms (other than 1 ,
• the PTT can contain minor amounts of other comonomers, such comonomers are usually selected so that they do not have a significant adverse affect on properties.
• Such other comonomers include 5-sodium- sulfoisophthalate, for example, at a level in the range of about 0.2 to 5 mole %.
• Very small amounts of trifunctional comonomers, for example trimellitic acid, can be incorporated for viscosity control.
• the PTT can be blended with up to 30 mole percent of other polymers. Examples are polyesters prepared from other diols, such as those recited supra.
• the PTT contains at least 85 mol% of trimethylene terephthalate repeat units. In a further embodiment, the PTT contains at least 90 mol% of trimethylene terephthalate repeat units, In a still further embodiment the PTT contains at least 98 mol- % of of trimethylene terephthalate repeat units. In a still further embodiment the PTT contains 100 mol% of trimethylene terephthalate repeat units.
• suitable PTT is characterized by an intrinsic viscosity (IV) in the range of 0.70 to 2.0 dl/g. In a further embodiment, suitable PTT is characterized by an IV in the range of 0.80 to 1.5 dl/g. In a still further embodiment, suitable PTT is characterized by an IV in the range of 0.90 to 1.2 dl/g.
• IV intrinsic viscosity
• suitable PTT is characterized by a number average molecular weight (M n ) in the range of 10,000 to 40,000 Da. In a further embodiment suitable PTT is characterized by M n in the range of 20,000 to 25,000 Da.
• a polystyrene is selected from the group consisting of polystyrene homopolymer, ⁇ -methyl-polystyrene, and styrene-butadiene copolymers, and blends thereof.
• the polystyrene is a polystyrene homopolymer.
• the polystyrene homopolymer is characterized by M n in the range of 5,000 to 300,000 Da.
• M n of the polystyrene homopolymer is in the range of 50,000 to 200,000 Da.
• M n of the polystyrene homopolymer is in the range of 75,000 to 200,000 Da. In a still further embodiment, M n of the polystyrene homopolymer is in the range of 120,000 to 150,000 Da.
• polystyrenes can be isotactic, atactic, or syndiotactic. High molecular weight atactic polystyrene is preferred. Polystyrenes useful in this invention are commercially available from many suppliers including Dow Chemical Co. (Midland, Mich.), BASF (Mount Olive, N.J.) and Sigma-Aldhch (Saint Louis, Mo.).
• PTT and PS are melt blended and, then, extruded in the form of a strand that is subsequently cut into pellets.
• Other forms of melt blending and subsequent comminution, such as into flake, chips, or powder, can also be performed.
• the pellets are then remelted, diluted with additional PTT, and extruded into filaments.
• the pellets are remelted and extruded into films, with our without dilution.
• the polymer blend comprises poly(trimethylene terephthalate) and polystyrene. In some embodiments, these will be the only two materials in the blend and they will total 100 weight %. However, in many instances the blend will have other ingredients such as are commonly included in polyester polymer compositions in commercial use. Such additives include but are not limited to other polymers, plasticizers, UV absorbers, flame retardants, dyestuffs, and so on. Thus the total of the
• poly(trimethylene terephthalate) and polystyrene will not be 100 weight %.
• the composition is in the form of a solid wherein the polystyrene is in the form of particles having an average size of less than 500 nanometers, the polystyrene is polystyrene homopolymer at a concentration of 20 to 30%; and, the poly (trimethylene arylate) is poly (thmethylene terephthalate) comprising at least 98 mol% of trimethylene terephthalate monomer units.
• the invention provides a process comprising combining poly (trimethylene arylate) and 15 % to 40% by weight on the basis of total polymer weight, of polystyrene, melting the poly (trimethylene arylate) and polystyrene, and melt blending the melted poly (trimethylene arylate) and polystyrene in a high shear melt mixer to provide a melt composition comprising a poly (trimethylene arylate) and a polystyrene dispersed therewithin.
• the polystyrene at a concentration 15% to 40 wt% on the basis of total polymer weight.
• the poly(trimethylene arylate) is PTT.
• the PS is at a
• the PTT is characterized by an IV in the range of 0.90 to 1.2 dl/g.
• the PS is PS
• homopolymer is characterized by a number average molecular weight of 75,000 to 200, 000 Da.
• the polystyrene is polystyrene homopolymer at a concentration of 20 to 30% and is characterized by a number average molecular weight of 75,000 to
• the poly (trimethylene arylate) is poly (trimethylene terephthalate) comprising 98 mol-% of trimethylene terephthalate monomer units and whereof the intrinsic viscosity is in the range of 0.90 to 1.2 dl/g.
• the PTT and PS can be melt blended by any known technique, including but not limited to an embodiment (a) comprising melting and mixing simultaneously from separate feeds, as, for example, in a co-fed twin screw extruder; an embodiment (b) comprising pre-mixing the unmelted polymers in a separate apparatus before melt blending, as, for example, in tumble blending pellets or flake of the polymers prior to feeding a twin-screw extruder, or an embodiment (c) comprising melting each polymer separately and then mixing the melts, as, for example, in feeding a twin screw extruder with the PTT in molten form from a continuous melt polymerizer, and feeding the twin-extruder with PS in molten form from a satellite single or twin screw extruder.
• an embodiment (a) comprising melting and mixing simultaneously from separate feeds as, for example, in a co-fed twin screw extruder
• compositions include, but are not limited to, the size of the PS particles formed within the PTT matrix, and the volume homogeneity of the PS particle distribution within the PTT matrix. Average particle size greater than 500 nm is not desirable from the standpoint of good fiber spinning performance. Additionally, spinning of uniform fiber, both along a single end, and end to end, depends expressly upon the homogeneity of the volume distribution of the PS particles. It is expected that in the actual melt processing thereof, the PS particles melt to form molten droplets that are dispersed within a molten PTT matrix.
• melt temperature in the melt mixer should be above the melting points of both the PTT and the PS but below the lowest decomposition temperature of any of the ingredients. Specific temperatures will depend upon the particular attributes of the polymers employed. In typical practice, melt temperature is in the range of 200 0 C to 270 0 C.
• Both fine particle size of PS and volume homogeneity of the dispersion of PS in the PTT depend upon the application of high shear melt blending. This is especially true for the high concentrations of PS employed in the compositions hereof.
• the amount of shear force applied to the melt depends upon the rotational speed of the mixing elements, the viscosity of the melt, and the residence time of the melt in the mixing zone. If the shear forces are too low there is a tendency for the PS not to break up to begin with, or to agglomerate rapidly into droplets greater than 500nm in size.
• melt blending process can be performed both batchwise and continuously.
• High shear mixers such as are commonly employed in the art of polymer compounding are suitable. Examples of suitable
• high shear batch mixers include, but are not limited to, Banbury mixers and Brabender mixers.
• continuous high shear mixers include co-rotating twin-screw extruders and Farrel
• Counter-rotating twin screw extruders are also suitable.
• suitable high shear mixers are those that are capable of exerting on a polymer melt a minimum shear rate of 50/s, with 100/s preferred.
• the PTT/PS blend so produced is extruded into one or more strands about 1/8" to 3/16" in diameter that are then cut up into pellets.
• the pellets so produced can be employed as they are in injection or compression molding, and melt casting of films.
• the pellets so produced can also be employed as a concentrate or masterbatch useful in the production of melt spun fibers.
• the pellets so produced comprise PTT polymer, described supra, and PS polymer, described supra, wherein the PS polymer is in the form of particles less than or equal to 500 nm in size dispersed in a continuous phase formed by the PTT polymer.
• the concentration of the PS particles is in the range of 15 % to 40 wt%. In a further embodiment, the concentration of PS particles is in the range of 20 % to 30 wt%.
• the concentrate pellets are melt blended with a PTT diluent to form a homogenous melt blend that has a lower concentration of PS than is found in the concentrate.
• the PTT diluent may or may not contain PS, but if it does contain PS, the
• concentrate pellets are combined with diluent PTT to form a
• composition comprising 0.5 to 1.5 wt% of PS. This composition shall be known as the "spinning blend.”
• both the concentrate and the diluent may be in the form of chips, flakes, or powder instead of pellets.
• pellets any or all of the alternative forms may be substituted therefor.
• extrusion-processing performance is best when the polymeric components are fed as pellets rather than chips, flakes, or powder.
• the PTT diluent and the concentrate pellets may be combined in any of a variety of ways.
• the diluent is initially in the form of pellets.
• the pellets of diluent and concentrate are first tumble-blended and the pellet blend so formed fed to a high shear melt mixer, either batch or continuous.
• the diluent can be in the form of a melt and the concentrate pellets fed thereinto in a high shear mixer.
• the diluent is fed as a melt from a continuous melt polymerizer to a twin screw extruder, and downstream from the point of introduction of the diluent, the concentrate pellets are fed to a satellite extruder that melts and feeds the concentrate in molten form into the diluent melt stream.
• This embodiment is shown schematically in Figure 1.
• PTT is produced in a continuous melt polymerizer, 1, from which it is conveyed in molten form via transfer line, 2, to a twin-screw extruder, 3.
• the concentrate pellets are fed via a weight-loss feeder, 4, or other pellet feeder means, to a satellite extruder, 5, wherein the concentrate pellet is melted and fed in molten form via transfer line, 6, to twin-screw extruder, 3, either at or upstream from the mixing zone of the twin-screw extruder, 3.
• a PTT/PS melt blend of the concentrate and diluent is formed in the twin-screw extruder.
• the resulting melt blend is fed via transfer line, 7, to a spin block comprising a spinneret, 8, from which continuous filaments, 9, are extruded.
• the resulting PTT/PS melt blend is extruded as a strand which is subsequently cut into pellets.
• the pellets so formed shall be referred to as "PTT/PS blend pellets.”
• the PTT/PS blend pellets can then be fed to an extruder to be melted and fed to a spinneret for melt spinning of fiber.
• the polymer melt is fed to the spinneret via a transfer line.
• the melt input to the transfer line from the extruder is in general quite turbulent.
• the spinneret feed must be laminar in order to achieve uniform flow through the plurality of holes in the spinneret. It is in the transfer line that the melt flow shifts from turbulent to laminar.
• threshold concentration of PS there is a threshold concentration of PS above which an unacceptable degree of PS agglomeration occurs, causing the PS particle size to exceed 500 nm, thus interfering with the achievement of the desired high spinning speed.
• the particular value of the threshold concentration depends upon the length of the transfer line, the viscosities of the PS and PTT, and the residence time of the melt in the transfer line.
• a theoretical model of laminar flow of the spinning composition hereof shows that a concentration of PS exists below which agglomeration and particle growth do not occur. It is desirable to operate the process hereof in that region.
• the specific value of the needed concentration depends upon the shear rate and residence time applied to the melt in laminar flow. It is found for example that at a shear rate of 5/s and a residence time of 6 seconds as found in a transfer line, the needed concentration of PS is 1.2%.
• Fiber spinning can be accomplished using conventional apparatus and procedures that are in widespread commercial use. As a practical matter, it is found that for spinning fine denier filaments of 3 denier per filament (dpf) or lower, a PS concentration of > 3% leads to a degradation in mechanical properties of the fiber so produced. It is further found that at 5% PS, fine denier filaments cannot be melt spun at all.
• dpf denier per filament
• the PTT/PS blend produced suitable for fiber spinning is N-(2-aminoethyl)-2-aminoethyl-N-(2-aminoethyl)-2-aminoethyl-N-(2-aminoethyl)-2-aminoethyl-N-(2-aminoethyl)-2-aminoethyl-N-(2-aminoethyl)
• the polymer blend pellets Prior to melt spinning, the polymer blend pellets are preferably dried to a moisture level of ⁇ 30 ppm to avoid hydrolytic degradation during melt spinning. Any means for drying known in the art is satisfactory. In one embodiment, a closed loop hot air dryer is employed. Typically, the PTT/PS blend is dried at 130 0 C and a dew point of ⁇ -40 0 C for 6 h. The thus dried PTT/PS polymer blend is melt spun at 250-265 0 C into fibers using conventional processing machines as appropriate for bulk continuous filaments (BCF), partially oriented yarn (POY), spin-draw yarn (SDY), and staple fiber.
• BCF bulk continuous filaments
• POY partially oriented yarn
• SDY spin-draw yarn
• the dried polymer blend pellets are fed to an extruder which melts the pellets and supplies the resulting melt to a metering pump, which delivers a volumetrically controlled flow of polymer into a heated spinning pack via a transfer line.
• the pump provide a pressure of 10-20 MPa to force the flow through the spinning pack, which contains filtration media (eg, a sand bed and a filter screen) to remove any particles larger than a few micrometers.
• the mass flow rate through the spinneret is controlled by the metering pump.
• the polymer exits into an air quench zone through a plurality of small holes in a thick plate of metal (the spinneret). While the number of holes and the dimensions thereof can vary greatly, typically a single spinneret hole has a diameter in the range of 0.2- 0.4 mm. A typical flow rate through a hole of that size tends to be in the range of about 1-5 g/min. Numerous cross- sectional shapes are employed for spinneret holes, although circular cross-section is most common. Typically a highly controlled rotating roll system through which the spun filaments are wound controls the line speed. The diameter of the filaments is determined by the flow rate and the take-up speed; and not by the spinneret hole size.
• the properties of the produced filaments are determined by the threadline dynamics, particularly in the region between the exit from the spinneret and the solidification point of the fibers, which is known as the quench zone.
• the specific design of the quench zone air flow rate across the emerging still motile fibers has very large effects on the quenched fiber properties.
• Both transverse (or lateral) quench and radial quench are in common use. After quenching or solidification, the fibers travel at the take-up speed, which is typically 100-200 times faster than the exit speed from the spinneret hole. Thus, considerable acceleration (and stretching) of the threadline occurs after emergence from the spinneret hole.
• the amount of orientation that is frozen into the spun fiber is directly related to the stress level in the fiber at the solidification point.
• Sorona ® Bright PTT resin (1.02 IV available from the DuPont Company, Wilmington, DE) polythmethylene terephthalate was combined with polystyrene (168 M KG 2 available from BASF) in the amounts shown in Table 1.
• the PTT was dried in a vacuum oven with a nitrogen purge at 120 0 C for 14 hours prior to use.
• the two polymers were individually weight-loss fed to the fourth barrel section of a Werner & Pfleiderer ZSK- 30 co-rotating twin screw extruder.
• the feed rates employed are shown in Table 1 in pounds per hour (pph).
• the extruder had a 30 mm diameter barrel constructed with 13 barrel sections provided in alternating arrangement with two kneading zones and three conveying sections, the extruder having an L/D ratio of 32. Each barrel section was independently heated. Sections 1 -4 were set at 25°C, Sections 5-13 were set at 210 0 C, the 3/16" strand die was also set at 210 0 C. A vacuum was applied to barrel segment 8. The screw speed was as indicated in Table 1. Table 1 also shows the composition of the feed, the rate of output, and the melt temperature. The polymer was quenched in water immediately upon exiting the die and was then pelletized using standard pelletizing equipment into 1/8" pellets.
• Sorona® Semi Dull PTT resin (1.02 IV - 0.3 wt-% TiO 2 , available from the DuPont Company) was combined with 8 wt% of the polystyrene of Examples 1 -6. The PTT was dried prior to use as in Examples 1 -6.
• the two polymers were independently fed by weight loss feeders at 184 pph of PTT and 16 pph of PS (using a K-tron S-200 single screw feeder and a K-tron K2ML-T20 twin screw spiral feeder for the PTT and PS, respectively, K-Tron International, Inc., Pitman, NJ) to the second barrel section of a 40 mm co-rotating twin-screw extruder (Werner & Pfleiderrer Corp., Ramsey, NJ) provided with 10 independently heated barrel sections.
• the throat temperature was 50 0 C
• barrel sections 1 -4 were set at 230 0 C
• barrel section 5 was set at 225 0 C
• barrel sections 6-9 were set at 200 0 C
• barrel section 10 was set at 245 0 C
• melt temperature using this heating profile was 255°C.
• the six output strands were water- quenched and pelletized into 1/8" pellets.
• the process for spinning was as shown in Figures 1 and 2 except that the continuous melt polymerizer shown in Figure 1 was replaced by a weight-loss pellet feeder.
• pellets of Sorona ® Semi Dull PTT resin were employed as the diluent polymers, as described supra.
• the pellets were fed to a 28 mm co-rotating twin-screw extruder (Werner & Pfleiderrer Corp., Ramsey, NJ) at 41.58 g/min.
• the 8 wt% PS/PTT pellets prepared supra were fed via a weight-loss feeder, 4, to a satellite extruder that has 4 independently heated barrel sections (Prism corotating twin screw extruder, Thermo Scientific,
• Barrel section 1 was set to 250 0 C and barrel sections 2- 4 were set to 260 0 C.
• a gear pump set to 260°C delivered the 8 wt% PS/PTT polymer melt to the 28 mm extruder, 3, in barrel section 2, at a rate of 4.62 g/min.
• the 28 mm twin-screw extruder was provided with 10 barrel sections set at 265 0 C.
• the resulting melt temperature at the die exit was 265°C.
• the 8 wt% PS/PTT melt blend of the concentrate and diluent PTT melt were mixed to form a 0.8 wt% PS/PTT polymer melt blend, which was fed via transfer line, 7, to a spin pack, 8, containing a sand filter (25/50 layer on top of a 50/325 mesh layer) to the 34 hole spinneret.
• the holes were of round cross-section and 0.012" in diameter and 0.022" in length from which continuous 2.2 denier per filament yarns were extruded.
• FIG. 2 is a schematic representation of the fiber spinning process.
• 34 filaments, 22, were extruded through spinneret,21.
• the filaments passed through a cooling zone, 23, formed into a bundle, and passed over a finish applicator, 24.
• the cooling zone comprised cross-flow quench air at room temperature and at 60% relative humidity and a velocity of 40 feet/min.
• the filament bundle passed to a pair of feed rolls, 25, set at 75 0 C.
• the filament bundle was wrapped around the feed rolls 6 times. From the feed rolls, the filament bundle was passed to a pair of draw rolls set at 125 0 C, wrapped around the draw rolls 8 times.
• Draw roll speed was 4500 m/min while the feed roll speed was 2000 m/min.
• the filament bundle was passed to a pair of let-down rolls, 27, operated at room temperature and at a speed 1 - 2% faster than the draw rolls speed.
• the filament bundle was wrapped around the let-down rolls 10 times.
• the filament bundle passed though an interlace jet, and thence to a wind-up operated at 4445 m/min.
• the fiber so prepared was characterized as 2.32 dpf, with a tenacity of 2.84 g/denier.
• Sorona ® Bright PTT resin was combined with 20 weight% of the polystyrene of Examples 1 -6. The PTT was dried prior to use as in
• Examples 1 -6 The two polymers were independently fed by weight loss feeders at 28 pph of PTT and 7 pph PS into the 4 th barrel section of a Werner & Pfleiderer ZSK-30 co-rotating twin screw extruder provided with 13 independently heated barrel sections.
• the throat temperature and first barrel temperature were set at 190 0 C, with the following 12 sections set at 210 0 C.
• the polymer was extruded through a single stand die with a 3/16" hole. The polymer strand was then water-quenched and pelletized into 1/8" pellets.
• polystyrene was more opaque than the film without polystyrene, while feeling the same with relation to bhttleness and tensile properties.
• Example 8 0.4 lbs of the PTT/PS pellets produced in Example 8 were mixed with 9.6 lbs of Sorona® Bright PTT resin pellets containing no PS.
• the resulting pellet mixture was fed to a Werner & Pfleiderer extruder with a 28 mm diameter barrel and 6 barrel segments each set to 240 0 C. Screw speed was 150 rpm. a melt temperature of 268°C was determined by hand at the exit of the extruder.
• the extruder output was fed to a 10 inch coat hanger film die set at 239 0 C. The die gap was set at 0.010 in and the die pressure was 296 psi. A film was cast onto a water-cooled rotating casting drum, and then to a wind-up operating at 8 feet per minute.
• the prepared film was found to exhibit at a uniform thickness of 0.002 in and was 10 in wide.
• a section of the film so produced was examined by transmission electron microscopy (TEM). By visual inspection, the preponderance of PS particles was characterized by 150 nm particle size.
• Sorona® Semi Dull PTT resin is combined with 20 wt% of the polystyrene of Examples 1 -6. The PTT is dried prior to use as in
• Examples 1 -6 The two polymers are independently fed by weight loss feeders at 160 pph of PTT and 40 pph of PS (using a K-tron S-200 single screw feeder and a K-tron K2ML-T20 twin screw spiral feeder for the PTT and PS, respectively, K-Tron International, Inc., Pitman, NJ) to the second barrel section of a 40 mm co-rotating twin-screw extruder (Werner & Pfleiderrer Corp., Ramsey, NJ) provided with 10 independently heated barrel sections.
• a 40 mm co-rotating twin-screw extruder Wowelner & Pfleiderrer Corp., Ramsey, NJ
• the throat temperature is 50 0 C
• barrel sections 1-4 are set at 230 0 C
• barrel section 5 is set at 225 0 C
• barrel sections 6-9 are set at 200 0 C
• barrel section 10 is set at 245 0 C.
• the 6-hole strand die provided with 3/16" holes, is set at 245°C.
• the six output strands are water-quenched and pelletized into 1/8" PTT/20%PS pellets.
• the process for spinning is as shown in Figures 1 and 2 except that the continuous melt polymehzer shown in Figure 1 is replaced by a weight-loss pellet feeder.
• pellets of Sorona ® Semi Dull PTT resin are fed to a 28 mm co-rotating twin-screw extruder (Werner & Pfleiderrer Corp., Ramsey, NJ) at 44.35 g/min.
• the PTT/20%PS pellets from the preceding paragraph are fed via a weight-loss feeder, 4, to a satellite extruder that has 4 independently heated barrel sections (Prism corotating twin screw extruder, Thermo Scientific, Waltham, MA), 5.
• Barrel section 1 is set to 250 0 C and barrel sections 2-4 are set to 260 0 C.
• a gear pump set to 260°C delivers the 8 wt% PS/PTT polymer melt to the 28 mm extruder, 3, in barrel section 2, at a rate of 1.85 g/min.
• the 28 mm twin-screw extruder is provided with 10 barrel sections set at 265 0 C.
• the 20 wt% PS/PTT melt blend of the concentrate and diluent PTT melt are mixed to form a 0.8 wt% PS/PTT polymer melt blend, which is fed via transfer line, 7, to a spin pack, 8, containing a sand filter (25/50 layer on top of a 50/325 mesh layer) to the 34 hole spinneret.
• the holes are of round cross-section and 0.012" in diameter and 0.022" in length from which continuous 2.2 denier per filament yarns are extruded.
• FIG. 2 is a schematic representation of the fiber spinning process.
• 34 filaments, 22, are extruded through spinneret, 21.
• the filaments pass through a cooling zone, 23, are formed into a bundle, and pass over a finish applicator, 24.
• the cooling zone comprises cross-flow quench air at room temperature and at 60% relative humidity and a velocity of 40 feet/min.
• the filament bundle passes to a pair of feed rolls, 25, set at 75 0 C.
• the filament bundle is wrapped around the feed rolls 6 times.
• the filament bundle passes to a pair of draw rolls 26 set at 125 0 C, wrapped around the draw rolls 8 times.
• Draw roll speed is 4500 m/min while the feed roll speed is 2000 m/min.
• the filament bundle passes to a pair of let-down rolls, 27, operated at room temperature and at a speed 1 -2% faster than the draw rolls speed.
• the filament bundle is wrapped around the let-down rolls 10 times.
• the filament bundle passes though an interlace jet 28, and thence to a wind-up 29 operated at 4445 m/min.
• the fiber so prepared is characterized as 2.32 dpf, with a tenacity of 2.84 g/denier.

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• 2010
  • 2010-08-20 TW TW099128019A patent/TWI512039B/zh not_active IP Right Cessation
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